Auger Spectroscopic Evidence That Plasma Anodization Involves Mass Transfer from the Cathode to the Anode

Abstract

Auger spectroscopic evidence is presented that cathode material is transported to the anode during plasma anodization, even when the anode is facing away from the cathode and is located on the back of a shield. In the preparation of the plasma oxide samples, anodes of Ta, Nb, and Cu and cathodes of Ta, Nb, Al, and C have been used in various combinations. The Auger spectroscopic results indicate that cathode material does not deposit on the anode unless the anode is passing a current and that the oxide on the anode formed by plasma anodization generally has two layers, with the outer layer consisting of oxide of the cathode material and the inner layer consisting of oxide of the anode material. Evidence is presented which suggests that the transfer of cathode material to the anode is an integral part of plasma anodization.